GNU Radio 2.x: char.h Source File

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# char.h

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    00001 /* Include file to configure the RS codec for character symbols
    00002  *
    00003  * Copyright 2002, Phil Karn, KA9Q
    00004  * May be used under the terms of the GNU General Public License (GPL)
    00005  */
    00006
    00007 #define DTYPE unsigned char
    00008
    00009 /* Reed-Solomon codec control block */
    00010 struct rs {
    00011   unsigned int mm;              /* Bits per symbol */
    00012   unsigned int nn;              /* Symbols per block (= (1<<mm)-1) */
    00013   unsigned char *alpha_to;      /* log lookup table */
    00014   unsigned char *index_of;      /* Antilog lookup table */
    00015   unsigned char *genpoly;       /* Generator polynomial */
    00016   unsigned int nroots;     /* Number of generator roots = number of parity symbols */
    00017   unsigned char fcr;        /* First consecutive root, index form */
    00018   unsigned char prim;       /* Primitive element, index form */
    00019   unsigned char iprim;      /* prim-th root of 1, index form */
    00020 };
    00021
    00022 static inline int modnn(struct rs *rs,int x){
    00023   while (x >= rs->nn) {
    00024     x -= rs->nn;
    00025     x = (x >> rs->mm) + (x & rs->nn);
    00026   }
    00027   return x;
    00028 }
    00029 #define MODNN(x) modnn(rs,x)
    00030
    00031 #define MM (rs->mm)
    00032 #define NN (rs->nn)
    00033 #define ALPHA_TO (rs->alpha_to)
    00034 #define INDEX_OF (rs->index_of)
    00035 #define GENPOLY (rs->genpoly)
    00036 #define NROOTS (rs->nroots)
    00037 #define FCR (rs->fcr)
    00038 #define PRIM (rs->prim)
    00039 #define IPRIM (rs->iprim)
    00040 #define A0 (NN)
    00041
    00042 #define ENCODE_RS encode_rs_char
    00043 #define DECODE_RS decode_rs_char
    00044 #define INIT_RS init_rs_char
    00045 #define FREE_RS free_rs_char
    00046
    00047 void ENCODE_RS(void *p,DTYPE *data,DTYPE *parity);
    00048 int DECODE_RS(void *p,DTYPE *data,int *eras_pos,int no_eras);
    00049 void *INIT_RS(unsigned int symsize,unsigned int gfpoly,unsigned int fcr,
    00050                    unsigned int prim,unsigned int nroots);
    00051 void FREE_RS(void *p);
    00052
    00053
    00054
    00055
    00056